1. Field of the Invention
The present invention relates to contacts of electrical connectors. More specifically, the present invention relates to fusible members and the contacts for connecting electrical connectors to substrates.
2. Description of the Related Art
Electrical connectors are used to place electrical devices in communication with one another, for example, to connect an electrical device or cable to a circuit board. A typical connector includes one or more contacts that electrically and mechanically connect the connector to one or more corresponding pads of a circuit board. The electrical and mechanical connection between a contact and a pad is typically provided by a fusible material, such as solder.
U.S. Pat. No. 7,837,522 discloses a method of attaching solder to a contact. FIGS. 14A-14C show a contact 210 and a solder member 220. As shown in FIG. 14A, the contact 210 includes a tail section 213 extending from the bottom of a body section 212. A peg 215 is cut or stamped from the tail section 213 of the contact 210 and protrudes from a front surface 210A of the contact 210. As shown in FIG. 14C, the solder member 220 includes a depression 222 that is formed by the peg 215 of the contact 210 pressing into the solder member 220 when the solder member 220 is attached to the contact 210.
As shown in FIGS. 14B and 14C, the solder member 220 is located only on the front surface 210A of the contact 210 when the solder member 220 is attached to the contact 210. Accordingly, when the solder member 220 is reflowed (i.e., melted) to attach to the contact 210 to a pad of a circuit board, the solder of the solder member 220 predominantly remains at the front surface 210A of the contact 210. Thus, because a low proportion of the solder flows to a rear surface 210B of the contact 210, the electrical and mechanical connection between the contact 210 to the pad of the circuit board is weaker at the rear surface 210B as compared to the front surface 210A. As a result, the connection between the contact 210 and the pad of the circuit board is more likely to break than if the solder of the solder member 220 was more evenly distributed between the front surface 210A and the rear surface 210B of the solder member 220.
Further, when the contact 210 is attached to the pad of the circuit board, the optimal location for the tail section 213 of the contact 210 is centered with respect to the pad of the circuit board. However, since the solder member 220 is attached only at the front surface 210A of the contact 210, the solder member 220 is offset from the center of the pad of the circuit board. Accordingly, the pad of the circuit board must have a large surface area to accommodate the bottom surfaces of both the solder member 220 and the tail section 213 of the contact 210.